8Engle, R F and Granger, C W J. (1987 ) ,Cointegration and error correction : representation, estimation and testing[J]. Econometrics,55 : 251 - 286.
9Geweke J , Meese,R and Dent,W. (1983),Comparing alternative tests of causality in temporal systems:analytical and experimental evidence [J]. Journal of Econometrics,21 :161- 196.
10Dichey D A and Fuller,W A. (1979) ,Distribution of.the estimators for autoregressive time series with a unit root[J] ,Journal of the American Statistical Association, 74: 47 - 431.